<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div#box{
            text-align: center;
        }
        div#box div#btn{
            margin: auto;
            width: 50px;
            height: 50px;
            line-height: 50px;
            background: #ddd;
            border-radius: 100%;
            color: #fff;
        }
    </style>
</head>
<body>
    <div id="box">
        <div id="btn">开</div>
        <img src="img/pic_bulboff.gif" alt="" id="img">
    </div>

    <script>
        (function(){
            var btn = document.querySelector('#btn');
            var img = document.querySelector('#img');
            btn.onclick = function(){
                if(this.innerHTML == '开'){
                    img.src = "img/pic_bulbon.gif";
                    this.innerHTML = '关';
                    this.style.background = 'green';
                } else{
                    img.src = "img/pic_bulboff.gif";
                    this.innerHTML = '开';
                    this.style.background = '#ddd';
                }
            }
        } ())
    </script>
</body>
</html>